1. Field of the Invention
This invention relates to a tool for the removal of water from coal seam and/or coal bed methane wells, and the removal of hydrocarbon in oil/condensate wells, utilizing injected natural gas.
2. Description of the Related Art
Conventional tools, for removing such fluids from a well, usually inject natural gas as a xe2x80x9cpower fluidxe2x80x9d along an outer pipe to exit at the bottom of the tool into an inner coaxial pipe. This creates, using a venturi effect, an upward gas stream in the inner pipe to facilitate flow of a water/debris/etc. mixture from the well. Examples of such conventional pumps follow.
U.S. Pat. No. 4,332,529 appears to show a primary and secondary entry points of fluid into the upward stream.
Italian Patent No. 425,050 appears to show an apparatus using compressed air for bringing water and mud to the surface. The apparatus has two, angled, compressed air outlets to the upward stream.
Polish Patent No. 42192 appears to show the introduction (and re-introduction) of fluid into a stream at successive points along the upward stream, via angled inlets a and c.
U.S. Pat. No. 4,815,942 appears to illustrate the introduction of fluid at a first inlet end via curved nozzles, and downstream therefrom.
U.S. Pat. No. 4,372,712 appears to show a fluid flow in a first tube, which is augmented by a secondary fluid flow downstream created by an inducer and an injector.
Russian Patent No. 1244391 appears to show a well ejection pump that uses two fluid fed nozzles at different elevations of the pump for improving pump output.
U.S. Pat. No. 2,100,185 similarly relates to a jet pump with dual steam inputs for producing a vacuum inside the pump.
U.S. Pat. No. 3,592,562 shows gasses that move from an outer tube into an inner tube at longitudinally different heights (jet passage and bore) relative to the bottom of the nozzle, one facing upstream and the other downstream.
U.S. Pat. No. 4,028,009 and Japanese Reference No. 6-147,199 similarly appears to show a tube having sets of longitudinally spaced angled ports.
Russian Patent No. 1352098 appears to show first upstream rotating nozzles, and a relatively downstream entry point at an active nozzle for introduction of fluid moving along an outer tube and into the inner tube.
U.S. Pat. No. 4,473,186 relates to an annular primary injector, an ejector with a converging inlet section and a diverging diffuser section.
U.S. Pat. No. 4,310,288 shows a set of circularly spaced, tangentially disposed nozzles which allow fluid to enter an inner tube fluid flow from an outer tube, and secondary outlets.
U.S. Pat. No. 4,781,537 illustrates the use of primary and secondary fluid inputs for an injector.
U.S. Pat. No. 3,857,651 relates to a multi-member tube, wherein each has a ring with angled inlets.
This prior art, however, still does not disclose or teach a fluid extracting pump including, in combination, inner and outer coaxial tubes, primary angled gas outlets near to a pump central inlet, convergence and divergence of the fluid pate and/or a plurality of secondary gas outlets upstream the central inlet for introduction of additional gas, which enhance the venturi effect, provide atomization, create a fluid envelope to prevent sticking, and prevent debris fall back.
Accordingly, it is a purpose of the present invention to provide a more efficient pump for removing a fluid/debris/etc. mixture from a natural gas or hydrocarbon well,
It is another object of the present invention to provide a dewatering tool that includes no moving parts, thereby extending the useful life of the tool.
It is another object of the present invention to provide a dewatering tool that allows chemicals to be added to the power gas to promote longer run times for the well.
It is still another object of the present invention to provide a dewatering pump which can operate in fluid levels lower than the height of the pump.
It is a further object of the present invention to provide a power fluid assisted dewatering tool, wherein the flow of the power fluid can be regulated remotely of the tool.
It is another purpose of the present invention to provide a tool using both primary and secondary power gas outlets for a pump to facilitate upward movement of a fluid stream.
It is a further purpose of the present invention to provide a well dewatering tool including a plurality of secondary gas outlets for introduction of additional gas into the venturi area downstream from a set of primary gas outlets, resulting in atomization, a fluid envelope and debris fall back prevention.
Further, it is an object of the present invention to provide a dewatering tool having a pump with successive converging and diverging surfaces, and a supplemental introduction of power fluid at the intersection of the converging and diverging surfaces, to enhance a venturi effect of the pump.
To achieve the foregoing and other purposes of the present invention, there is provided a tool with a dewatering natural gas-assisted pump including a nozzle at a central inlet of the tool. The nozzle has a number of primary angled gas outlets, each with a first end opening to a space formed between outer and inner tubes of a pipe string, and the other end opening to the interior of the inner tube. These angled primary outlets allow the gas to accelerate, contributing to the venturi effect. The fluids/debris/etc. mixture moves from the nozzle to an eductor having an inwardly (relative to a tool central axis) inclined interior surface, which causes the mixture to converge. Then, via a diffuser, the mixture diverges along an outwardly inclined interior surface thereof to the inner tube, in which the mixture moves to the surface. As the mixture is leaving the eductor, however, it is further accelerated, i.e., the venturi enhanced, by secondary angled gas outlets formed in the diffuser which introduce additional gas from the space, between the diffuser and eductor, and into the interior of the inner tube, downstream of the primary outlets. When this gas is introduced at the secondary outlets, the mixture is also effectively atomized to facilitate movement of the mixture up the tool. The injected gas also serves to form a type of fluid envelope around the ascending mixture, which helps prevent the mixture from sticking to the inner tube. Also, by introducing additional gas above the central inlet, and downstream from the primary gas outlets, debris is less likely to fall back down the tool.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.